JP2005198446A - Transfer block system for distributed power supply - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the number of distributed power supplies to a requisite minimum that are paralleled off when there occurs an accident such as an earth fault in accordance with a system state at a system change even if a distribution system is temporarily changed in terms of a system by work or the like, and to constantly minimize an effect due to the accident, in the distribution system in which a plurality of the distributed power supplies such as photovoltaic power generating sets are aligned. <P>SOLUTION: Position information on the distributed power supplies 31A to 31C and switch state information in the system 21 are obtained and stored, it is individually discriminated under which distribution cable of a power substation each distributed power supply is, on the basis of the stored information, and transfer block signals are selectively transmitted to only the distributed power supplies 31B, 31C that are objects to be blocked in transfers, on the basis of the discrimination when the accident occurs in the system 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention cuts off power transmission from a distribution substation when an accident such as a ground fault occurs in a distribution system under a substation where a large number of distributed power sources such as solar power generation devices are arranged in parallel. The present invention relates to a distributed power supply transfer cut-off system in which a distributed power supply is disconnected from the distribution system by transfer cut-off.

  Recently, a distributed power source installed in a customer's house such as a factory, a building, or a general house, such as a solar power generation device using a solar cell, a wind power generator, a co-generator, etc. Distributed power supply systems that are connected in parallel to a power distribution system are becoming widespread (see, for example, Patent Documents 1 and 2).

  In this distributed power supply system, as shown in FIG. 5A, when an accident such as a ground fault occurs in the distribution system (distribution line) 21 under the distribution of the distribution substation 1A, The power transmission from the station 1A is cut off urgently, and the distributed power sources 31A to 31C arranged in parallel in the distribution system 21 under the substation 1A are disconnected (released in parallel). This is to prevent isolated operation of the distributed power source.

The above disconnection is performed when each distributed power source automatically detects that it has become a single operation state, but the one that has not been disconnected due to a detection failure or the like is performed by blocking transfer. Transfer interruption is a remote interruption control using a signal transmission line such as an optical line, and a transfer interruption signal for instructing the interruption control is transmitted from a remote interruption control device (also called a transfer interruption transmission device) on the substation 1A side. The The remote cutoff control device sends the above transfer cutoff signal to the equipment in the distribution system when there is a distributed power source that is subject to unblocked transfer cutoff after the protection relay on the substation 1A side detects the accident To do. Through this series of operations, all the distributed power sources 31A to 31C in the power distribution system 21 are disconnected when an accident occurs.
JP-A-11-89093 JP 2000-358330 A

  In the above-described distributed power supply transfer cut-off system, the present inventors have revealed that the following problems occur. That is, as shown in FIG. 5A, when the distribution system 21 is in a so-called always-on system, the distribution system 21 and each of the distributed power sources 31 </ b> A to 31 </ b> C parallel to the distribution system 21 are Each of them is under the substation 1A that constantly distributes power to the distribution system 21. When an accident occurs in this state, as described above, all the distributed power sources 31A to 31C in the distribution system 21 are all disconnected due to transfer interruption or the like.

  On the other hand, as shown in (b) of the figure, in the work time system in which the distribution lines of the power distribution system 21 are temporarily divided in some sections for work, the power distribution system 21 is 2 in the work section. A system change that is divided into the systems 21a and 21b occurs. In order to maintain the power distribution even in such a working system, only the system 21b on the side where the power transmission from the substation 1A that is normally distributed is cut off is separated from the two divided systems 21a and 21b into another substation 1B. System change to be connected to is temporarily made.

  Here, when an accident such as a ground fault occurs in one of the two divided systems 21a and 21b (21b) when the working system is formed, the accident occurs in the divided system 21b on the accident occurrence side. Only certain distributed power sources 31B and 31C need be disconnected, and the distributed power source 31A in the accident-free split system 21a is desirably maintained in parallel for power distribution stabilization and the like.

  However, in the above-described distributed power source transfer cutoff system, all the distributed power sources 31A to 31C in both the divided systems 21a and 21b are indiscriminately disconnected due to the transfer cutoff. Since the transfer cut-off signal for disconnecting the distributed power sources 31A to 31C is transmitted through a communication line different from the distribution system 21 (21a and 21b), the same as in the case of the normal system regardless of the system change at the time of work. It is distributed to each of the distributed power sources 31A to 31C under conditions. For this reason, there arises a problem that even the distributed power source 31A in the divided system 21a that should maintain power distribution on the accident-free side is unnecessarily disconnected.

  The present invention has been made in view of the above problems, and the main purpose of the present invention is to prevent accidents such as ground faults even when the distribution system under the distribution substation is temporarily changed for work. The distributed power supply that is disconnected when it occurs can be kept to the minimum necessary according to the system status at that time, and the interruption of the distributed power supply that can always minimize the effects of accidents To provide a system.

  The means of the present invention cuts off power transmission from a distribution substation when an accident such as a ground fault occurs in a distribution system under a substation where a large number of distributed power sources are arranged in parallel. In the distributed power transfer cutoff system, the remote cutoff control device which is the transmission side of the transfer cutoff signal includes the position information of the distributed power source and Obtaining and storing the switch state information in the system, distributed power source identification means for individually identifying which substation of which substation each subordinate power source is based on this stored information, A transfer target selection unit that selects a distributed power source that is a transfer interruption target based on identification by the identification unit when an accident occurs in the system, and a transfer target selection unit that selects the distributed power source selected by the selection unit. Characterized by comprising a transfer trip transmission means for transmitting a blocking signal.

  Furthermore, in the present invention, it is preferable that the following means is provided as a preferred embodiment of the above means.

  The transfer cut-off transmission means selectively transmits a transfer cut-off signal to one of the distributed power supplies subject to transfer cut-off selected by the selection means that does not transmit a disconnection signal notifying that it has been disconnected. Means for transmitting.

  Each distributed power source has a system parallel switch and a lead-in line in parallel with the power distribution system, and the system parallel switch is controlled by a PLC (power line communication) modem transfer cut-off device. Means for receiving a transfer cut-off signal via a PLC of a lead-in line and controlling the demultiplexing of the distributed power supply, and returning a cut-off signal indicating the cut-off state to the remote cut-off control device;

  Means characterized in that the transmission route of the transfer interruption signal and the disconnection signal is constituted by a wide-area transmission line using a long-distance communication line such as an optical line and a local transmission line using a PLC.

  Means characterized in that the wide-area transmission path is configured using an IP network and / or VPN.

  The local transmission line is formed in a service line section between the distribution line and the customer's house.

  The means for interrupting transfer with a PLC modem is configured to broadcast a disconnection signal.

  Even if the distribution system under the distribution substation is temporarily changed due to work, etc., a distributed power source that is disconnected when an accident such as a ground fault occurs is required according to the system status at that time It can be kept to a minimum, so that the effects of accidents can always be minimized.

  FIG. 1 is a schematic diagram showing an outline of a distributed power transfer interruption system according to the present invention. In the figure, a large number of distributed power sources 31A to 31C are arranged in parallel in a distribution system (distribution line) 21 under the distribution of the distribution substation 1A. The distributed power sources 31A to 31C are small-scale power generation systems such as solar power generation devices, and are installed in the customer homes 30A to 30C. Each of the distributed power sources 31 </ b> A to 31 </ b> C is connected to the power distribution system 21 via the system parallel switch 32 and the power lead-in line 22. In addition, 1B is another distribution substation that may be connected during the work system, and is disconnected from the distribution system 21 in the regular system shown in FIG.

  The system parallel switch 32 is controlled to open and close by a transfer interrupting device 33 with a PLC modem. This transfer interruption device 33 receives the transfer interruption signal transmitted from the remote interruption control device (transfer interruption transmission device) 11 installed on the distribution substation 1A side of the normal system, and opens and closes the system parallel switch 32. Take control. By this opening / closing control, parallel / disconnection control of the distributed power source is performed. The control result is returned to the remote cutoff control device 11. When the disconnection is performed, a disconnection signal is returned.

  A signal transmission path is formed between the remote cutoff control device 11 and the distributed power sources 31A to 31C. This signal transmission line is constructed using a wide-area transmission line using a long-distance communication line using an optical line and a local transmission line using PLC (power line communication). The wide-area transmission line is constructed using an existing optical line (private dedicated line) 51 laid along the distribution line of the distribution system 21 and an IP network and / or VPN 52. Moreover, PLC which forms a local transmission line is formed in the service line 22 section between the distribution line and the customer houses 30A-30C.

  The PLC is inferior in transmission speed or the like as compared to a dedicated communication line such as an optical line, but when used only for short-distance communication of the lead-in line 22 section, stable and reliable transmission can be performed. By using this PLC in the lead-in line 22 section, it is possible to omit the work of drawing a dedicated communication line for each customer house. Although this construction and their maintenance are very large due to the large number of objects, they can be made unnecessary by PLC using the lead-in wire 22.

  A transmission medium converter (media converter) is installed at a connection point between the distribution line of the distribution system 21 and the lead-in line 22 in order to mediate signal transmission between the wide area transmission line and the local transmission line. When the distribution line is an overhead line, the transmission medium converter is installed on a pole.

  The remote cutoff control device 11 constantly monitors the status of the power distribution system 21 and the distributed power sources 31A to 31C. When an accident such as a ground fault occurs in the system 21, the occurrence of the accident is detected by a protective relay operation or the like on the substation 1A side. Recognize that an accident occurred in

  When an accident occurs in the distribution system 21, the substation 1 </ b> A temporarily cuts off power transmission to the distribution system 21. At the same time, the remote cutoff control device 11 that has recognized the occurrence of the accident transmits a transfer cutoff signal to undistributed ones of the distributed power sources arranged in parallel with the distribution system 21.

  The remote cutoff control device 11 that is the transmission side of the transfer cutoff signal is communicatively connected so that information can be exchanged with the sales office 70 and the like via the IP network and / or the VPN 52. Thereby, the position information of the distributed power sources 31A to 31C and the switch state information in the system 21 can be acquired. The acquired information is stored while being updated sequentially.

  Based on the stored information, each distributed power source is individually identified as to which distribution line of which substation is under each distribution line. When an accident occurs in the system 31, a distributed power source that is a transfer interruption target is selected based on the identification, and a transfer interruption signal is selectively transmitted to the selected distributed power supply. In this case, the transfer cut-off signal is transmitted only to the distributed power supply that is not disconnected, and the transfer cut-off signal is not transmitted for the distributed power supply that has already been disconnected in order to avoid duplication of operation.

  FIG. 2 is a functional block diagram showing an embodiment of the main part of the remote shut-off control device 11. The figure mainly focuses on the communication and control system. The remote shutoff control device 11 includes a media converter (M / C) 12, a distributed power information acquisition unit 13, a distributed power source identification unit 14, It includes a transfer block target selection unit 15, a transfer block transmission unit 16, and the like. The media converter 12 is a kind of communication I / F (interface), and communication access to the VPN 52 and the like is performed via this I / F.

  The distributed power supply information acquisition means 13 automatically accesses the VPN 52 and acquires the position information of the distributed power supply 31 (31A to 31C) and the switch state information in the system 21. These pieces of information are obtained by periodically accessing, for example, a database of the sales office 70 storing the location and facility information of the customer's home 30 (30A to 30C), the line configuration of the power distribution system 21, and the like. The acquired information is stored in a database format. The stored information is constantly updated with newly acquired information.

  Based on the information acquired and stored by the information acquisition unit 13, the distributed power source identification unit 14 individually identifies which distribution power source 31 is under which distribution line of each substation. The transfer interruption target selection means 15 operates when an occurrence of an accident in the distribution system 21 is detected based on protection relay (Ry) operation information in the distribution substation 1A, and is identified by the identification means 14. Based on the above, the distributed power source 31 that is a transfer blocking target, that is, a disconnection control target is selected. The sorting result is output as information in a list format.

  The transfer cutoff signal transmission means 16 transmits a transfer cutoff signal to the distributed power source 31 selected as the transfer cutoff target. This transfer cut-off signal is transmitted to the distributed power supply 31 to be cut off through the existing optical line 51, the IP network and / or the VPN 52, and the PLC line formed by the lead-in line 22. The transmitted cut-off signal is received and processed by the transfer cut-off device with PLC modem 33 in the customer's house 30 where the distributed power supply 31 to be cut off is installed.

  The transfer interrupt device with PLC modem 33 that has received the transfer interrupt signal addressed to itself disconnects the distributed power source 31 by controlling the system parallel switch 32 to be turned off. Then, a disconnection signal indicating that the disconnection has been performed is returned to the transmission source. The disconnection signal is transmitted to the remote cutoff control device 11 via the PLC line by the lead-in line 22, the existing optical line 51, the IP network and / or the VPN 52.

  The remote cutoff control device 11 recognizes the distributed power source that has been disconnected by the above-mentioned disconnection signal, and removes the distributed power source that has been disconnected from the transfer cutoff target selection list. By continuing to transmit the transfer cutoff signal to the distributed power sources remaining in the list, finally, all the distributed power sources 31 subject to transfer cutoff are disconnected.

  In this case, the return source of the disconnection signal may not always be constant due to a system change or the like. In order to cope with this case as well, the disconnection signal may be broadcasted (broadcast transmission) to all the remote cutoff control devices 11 in the vicinity.

  Between the PLC line and the existing optical line 51, a transmission medium converter (media converter) 41 by an optical communication I / F 42 and a PLC modem 43 is installed. The converter 41 is installed between the distribution line and the lead-in line 22 as described above.

  FIG. 3 shows an operation flowchart in the main part of the remote shut-off control device 11. As shown in the figure, the remote shut-off control device 11 automatically recognizes the distributed power source that is subject to transfer shut-off in the event of an accident by periodically acquiring the position information of the distributed power source and the pole switch information. And memorize (S11, S12). At the same time, the occurrence of an accident in the distribution system is monitored based on the protection relay (Ry) operation information of the distribution line (S13).

  When an accident occurs in the power distribution system, a disconnection signal transmitted from the transfer interrupting device with PLC modem on the distributed power source side to be subject to transfer interruption is received and collated with the stored transfer interruption object (S14, S15). ). If there is a transfer blocking target that has not been disconnected, the transmission blocking signal is repeatedly transmitted to the target (S16, S17). As a result, all the distributed power sources that are subject to transfer interruption are finally disconnected.

  According to the configuration and operation described above, as shown in FIG. 4A, in a continuous system in which the distribution system 21 is continuously integrated, an accident such as a ground fault occurs in any of the distribution systems 21. When it occurs, all the distributed power sources 31A to 31C in the power distribution system 21 are targeted for transfer interruption based on identification and selection based on stored information acquired in advance. Thereby, in this case, all the distributed power sources 31A to 31C in the distribution system 21 are disconnected.

  Further, as shown in (b) of the figure, in the work time system in which the distribution lines in the distribution system 21 are temporarily divided in some sections for work, the distribution system 21 sandwiches the work sections. Thus, a state in which the two systems 21a and 21b are divided occurs. In order to maintain power distribution even in such a work-time system, out of the two systems 21a and 21b divided, the system 21b on the side where power transmission from the substation 1A that is normally distributed is cut off is transferred to another substation 1B. The system to be connected is changed temporarily.

  In this work system, when an accident such as a ground fault occurs in one of the two divided systems 21a and 21b (21b), the division on the accident occurrence side is performed based on identification and selection based on previously acquired storage information. Only the distributed power sources 31B and 31C in the system 21b are targeted for transfer interruption. Thereby, in this case, only the distributed power sources 31B and 31C in the split system 21b on the accident occurrence side are disconnected. The distributed power supply 31A in the accident-free split system 21a is maintained in parallel.

  As described above, even when the distribution system under the distribution substation is temporarily changed due to work, etc., the distributed power source that is to be disconnected when an accident such as a ground fault occurs, that is, the transfer interruption target, It can be set to the minimum necessary according to the system state at that time. Thereby, the influence by an accident can always be minimized.

  As mentioned above, although this invention was demonstrated based on the typical Example, this invention can have various aspects other than having mentioned above. For example, a transmission method of a transfer interruption signal or a disconnection signal, particularly a portion near the customer's house, so-called last one mile, may use a wired method other than PLC or a wireless method such as PHS or wireless LAN.

  Even if the distribution system under the distribution substation is temporarily changed due to work, etc., a distributed power source that is disconnected when an accident such as a ground fault occurs is required according to the system status at that time It can be kept to a minimum, so that the effects of accidents can always be minimized.

1 is a schematic diagram showing an outline of a transfer blocking system for a distributed power source according to the present invention. It is a block diagram according to function which shows one Embodiment of the remote interruption | blocking control apparatus which makes the structure principal part of this invention. It is an operation | movement flowchart in the principal part of a remote cutoff control apparatus. It is a schematic diagram which shows operation | movement of the transfer interruption | blocking system for distributed power supplies by this invention according to the state of a power distribution system. It is a schematic diagram which shows the operation | movement of the transmission interruption | blocking system for the conventional distributed power supply according to the state of a power distribution system.

Explanation of symbols

1A Distribution substation (for regular system)
1B Power distribution substation (work system)
11 Remote cutoff control device (transfer cutoff transmission device)
12 Media converter (communication I / F)
DESCRIPTION OF SYMBOLS 13 Distributed power supply information acquisition means 14 Distributed power supply identification means 15 Transfer interruption | blocking object selection means 16 Transfer interruption | blocking transmission means 21 Distribution system (distribution line)
22 Lead-in wire 30A-30C Customer's house 31, 31A-31C Distributed power source 32 System parallel switch 33 Transfer interrupter with PLC modem 41 Transmission medium converter (media converter)
42 Optical communication I / F
43 PLC modem 51 Existing optical line (private private line)
52 IP network and / or VPN

Claims (7)

When an accident such as a ground fault occurs in a distribution system under a substation where many distributed power sources are connected in parallel, power transmission from the distribution substation is interrupted, and the above distributed power sources are remotely In the distributed power supply transfer cutoff system that is disconnected from the distribution system by control, the remote cutoff control device on the transmission side of the transfer cutoff signal is:
Acquire and store the position information of the distributed power source and the switch status information in the system, and based on this stored information, individually identify which substation of each substation is under which distribution line Distributed power source identification means,
Transfer target selection means for selecting a distributed power source that is subject to transfer interruption based on identification by the identification means when an accident occurs in the system,
A transfer cutoff system for a distributed power source, comprising: a transfer cutoff transmission unit that transmits a transfer cutoff signal to the distributed power source selected by the selection unit.   2. The transfer cutoff transmission means according to claim 1, wherein said transfer cutoff transmission means is selective to a distributed power source selected by said selection means that does not transmit a disconnection signal notifying that it has been disconnected. A transmission interruption system for a distributed power source, wherein a transmission interruption signal is transmitted to the power supply.   3. The distributed power source according to claim 1, wherein each distributed power source has a system parallel switch and a lead-in line in parallel with the power distribution system, and the system parallel switch is controlled by a PLC (power line communication) modem transfer cutoff device. The transfer interruption device with a modem receives the transfer interruption signal via the PLC of the lead-in line and controls the distributed power supply to be disconnected, and returns a disconnection signal indicating the disconnection state to the remote interruption control device. A transfer block system for distributed power supplies.   4. The transmission route for the transfer cut-off signal and the disconnection signal according to any one of claims 1 to 3, comprising a wide-area transmission line using a long-distance communication line such as an optical line and a local transmission line using a PLC. Transfer interruption system for distributed power supply.   4. The distributed power transfer blocking system according to claim 3, wherein the wide-area transmission path is configured using an IP network and / or a VPN.   6. The distributed power supply transfer blocking system according to claim 4, wherein the local transmission path is formed in a service line section between a distribution line and a customer's house. 7. The distributed power transfer cutoff system according to claim 4, wherein the PLC modem-attached transfer cutoff device is configured to broadcast a disconnection signal.

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